Such a cannula is known in the state of the art and is typically used for discharging oxygenized and/or cleaned blood into the aortic arch during heart-bypass surgery or during the use of an heart-lung-machine. Accordingly such a cannula is often named as aortic cannula. The application of a blood cannula is not restricted to field and accordingly the cannula can be used for any vessel.
The proximal end with the straight part of the tubular body has an inlet opening into which the blood is delivered from a pump, in particular a pump of a heart-lung-machine. The inlet opening may communicate with a hose connector. The blood passes through the straight part which provides a straight mean direction of flow. This straight mean direction corresponds to the geometrical middle axis of the straight part of the tubular body. The straight part leads into a bent part of the tubular body at its distal end thus redirecting the mean blood flow direction into a curved flow path, in particular essentially also corresponding to the geometric middle line of the bent part. This bent part leads into the outlet opening of the cannula.
The bent part of the tubular body assist insertion of the cannula into a vessel, particularly in curved vessels like the aortic arch.
On the outer surface of the tubular body a flange part which surrounds the tubular body may be positioned in the transition area between straight part and bent part. This flange part may help to position and/or fix the cannula with respect to the vessel and may also help to seal the punctured vessel.
Typical cannulas of the common kind provide a constant cross section of the distal part or even a tapered cross section in flow direction. Even though this helps insertion of the cannula into a vessel the disadvantage is that the blood is accelerated prior to exit. In combination with the surrounding vessel after insertion a venturi-effect may be observed which causes problems since it constricts the blood flow into smaller vessels branching off the aortic arch.